Summarize this article in one sentence.
Tap the Messages app icon, which resembles a white speech bubble on a green background. It's in the top-right corner of the screen. A new screen will open. In the "To" text field near the top of the screen, type in the phone number of the person whom you want to text. If the person whom you want to text is saved as a contact on your iPod Touch, you can just type in their name instead. It's a text box near the bottom of the page, just above the on-screen keyboard. Type in the message you want to send. To add a photo to your message, do the following:  Tap the camera icon to the left of the text field. Tap Photos. Select an album. Tap the photo you want to send. Tap Choose. It's a blue-and-white button on the far-right side of the screen. As long as you're connected to Wi-Fi, your message will be sent.

Summary:
Open your iPod Touch's  Messages. Tap the "Compose"  icon. Enter a phone number. Tap the text message field. Write your message. Add photos if you like. Tap the "Send" button.